Microdermatome



Feb. 5, 1963 c. P. MEEK -E'rAl. 3,076,461

i MICRODERMATOME Filed Dec. 51, 1956 2 SheetsSheet 1 f@ in M 1 I N VEN TOR 'ze Uz'm Parker Meek BY il? 1ML@ A TTOBNEYS Feb. 5,; 1963 c. P. MEEK ETAL MICRODERMATOME 2 Sheets-Sheet 2 Filed Dec. 5l, 1956 United States Patent Oiiice 3,076,461 Patented Feb.. 5,` 1963 3,076,461' mcnooERMAroME creer Parkes Meek, 10s reeksen Drive, amr s. P. wan, n., mswieie Leng een. efr Aiken, so. Filed Dee., s1, 1956, ser..` Ne.. 631,112

9 claims. (ci. tzesusiV j" This invention pertains to a method and apparatus for preparing a skin section for subsequent use in a skin grafting operation. More specifically, thev present invention relates to a method andA means for recutting split thickness skin grafts obtained by conventional techniques into extremely small units which, when transplanted to the injured areaof the: patients body, result in aV greatly increased margin of proliferation.

Thus, one of the primary objects of this invention is `to provide a method and apparatus for reducing a` section of human skin to substantially microscopic size to facilitate the transplantation thereof in a skin grafting operation. p

A further object of this invention is` to provide a device, which may be optionally referred to as a microdermatorne or a microtome, for effecting the section ilig of skin grafts.

A still further object of this invention is to provide adjustable means in a microdermatome for obtaining minute particles of skin graft of preselected and predetermined size.

Other and further objects of the present invention will become more manifest from a consideration of the following specification when read in, conjunction with the annexed drawings, in which: j

FIGA 1 i's a Side elevational view of a microdermatome constructed in accordance with the` present invention;

FIG: 2 is an end` elevational view of the microderm-a- `to'ne shown in FIG. l, this view being partially broken away to illustrate several component elements thereof;

o FIG. 3 is a top plany View ofthe skin mounting block illustrated FIG. 1 with a split width skin section and its plastic backing sheet mounted thereon having been 'subjected to 'the initial cutting operation.

FI'G. Al is an t'ar'ilargetzl detail fragmentary cross-sec tional view taken on the line of FIG. 3, looking lin the direction of the arrows;

MFIG. 5 is a topA pian view of the mounting bleek in Which the block i's shown as supporting the plastic back- Aing sheet, the 'split width skin section, and the plastic 'cover sheet with a 'portion thereof broken away to show -`ighe configuration `of the 'split width skinl section after the "finalV cutting operaties.

i 5 is an 'enlarged 'detail fragmentary cross-sec `tional viewtalken on the "line '6-6 of "Fl"G. '5, looking fin "the 'direction 'of the arrows, `and illustrating the second cutting speist-ren;

FIG. 7 `"is a .greatly enlarged perspective view of ione of the skin cubes obtained as la consequence of the two cutting opera-tions.

vReferring ynow more specifically tothe drawings, reference `numeral 20 designates,` in general, Va ,tmicrodermatone constructed in accordance with the teachings of -the :present invention. As'iillustrated therein, :the imicrot'me izo fis sent te comprise three basic units, namely, the 1b`as`e Z2, the split lwidth fs'kinfspeciinen mounting block i224, "and arotary `cutter rand `its support "26 -movable with respect to the mounting block zit.

b'ase 22 has 'substantially U-'s'hap'ed :configuration Las 'is 'seen gin the .end Velevational "View of FIG. ,2,` and V.includes 'a .big-ht .portion 28`iha`vlin-g lintegra'llyiformed sub- `estaiit'ially vertical ,side -wa'lls 30, 32. The side :walls 30,

"32. are xlaterally 'spaced and substantially parallel with respect to each other, and the upper ends thereof `lie flush in a plane common to both.

T he bight portion 28 is provided with a longitudinally extending substantially rectangular recess 34 to Serve purpose to be described.

Each of the side walls 3), 32 is undercut at 36, 38, respectively,v adjacent the upper surface of the bight` pror-l tion 28 to form a pair of longitudinally extending, laterally spaced and confronting guide channels. "ghe side walls 30, 252` are also provided with a plurality of downwardly inclined tapped openings 4,0, 42 which corni-,r1unicate at their inner ends` with the guide. channels 36, 38 respectively. As is seen in the drawings, the tapped open; ings 40, 42 receive therethrough manually operable holds down bolts 41, 43 having enlarged knurl'ed heads i4v and 46, respectively.

The upper ends of the side walls 30 32. are `each constructed with a downwardly extending, `substantially V- shaped guide groove 4S, 50 respectively, which extend longitudinally thereof lto serve a purpose'to be described, The upper end of the side wall 32 is also formed With a downwardly extending substantially U-shaped revs 52 disposed substantially parallel to the V-,shaped groove and is laterally spaced outwardly therefrom. gear rack 54 is xedly secured within the recess 52 withH the teeth 56 thereof terminating in the common plane of the upper ends of side walls 30, 32. Y

The skin specimen mounting block 24 iS formedy of a plurality of integrally formed substantially rectangular members arranged in tiers. As is illustrated in FIGS. 1 and 2, the lowermost one of these members provides a continuous peripheral flange 58 for the base member 60.

Reference numerals 58A, 53B, 58C and 58D designate the four sides of the flange.

The split width-skin section. supporting block 62 projects above the base member and the sides thereof Nare spaced inwardly therefrom to ,define continuous ,mar tginal peripheral surfaces .64, 6,6, 68 and 70 ,(,see P41-QS. 3 and 5). At spaced intervals, -the block 62 is pI-Ovdttj -with tapped openings 72 which receive Vsplit-headed ,screws 74 therein.

The screws 74 are adapted .to anchor one end of ,a plurality of helicoidal springs 76. The springs 47,6 are paired off and ,the other ends of each pair are hooked to a manually .operable handle 7.8 lof a mechanical :804 4through .the aperture 82.

The clamps are preferably of the type .disclosed in the United States ygrant of Letters Ratent issued .on No: venrber 13, 1923 to Leon H. Ashmore, No. 1,474, ,2, and the intended function thereof will be fully set forth below. lt should l,be noted, however, that spring means .84 constantly .tend to bias the clamp arms 86, 85 ofeach `clamp $0 to their tclosed position. i

"Ihe, rotary cutter support rv26 .comprises ,an inverted, Fsubstantially U-Hshaped ,frame thaving .a bight poltiQn 9,9 from which depend a pair of laterally `spaced and sub? stantially parallel Vside walls 9,2, ,194. Ihelou/ er ,ends of the side walls 92, 94 are formed with outwardly proiectifng longitudinally extending substantially `ll-Shaped .rails 96, 98, respectively, which ,are A"slidablyreceived within the guide grooves 48, 150.

The side twall 94 has an invertedgsubstantially U-shapegi .recess .100 ropening `inwardly from tthye Jrree rend thier-zeef, the lrecess being `defined vby :a largely arcuate `,end `Wall 94A `and opposed, spaced .and substantially parallel walls 94B, 94C. The side twall p9@ is bored ,to forni `an aperture 102 which ,iscoaxialy alignedewith a@ 4u,- .lar recess i104 .of the same diameter formed in .the d wall 94C. The opening to the recess 100 is aligned ,thefrack .54 and 4the .recess has disposed Stherein a`pinion ..106 having .teeth1,08 in ,mesh .with i.the raclt,teeth 56. The pinion 106 is iixedly mounted on an axle 110 by a press lit and the ends of the axle project laterally beyond the opposite sides thereof. As is clearly seen in FIG. 2, one end of the axle 110 is journalled for rotation in the circular recess 104 and the other end thereof is rotatably supported in the aperture and terminates in an integrally formed enlarged knurled knob 112.

'I'he side walls 92, 94, adjacent their upper ends are provided with confronting aligned bearing receiving recesses 114, 116, respectively, in which are disposed the ball bearings 118, 120. The inner end of the recess 114 is in open communication and is coaxially aligned with the inner end of a transversely extending bore 122 internally threaded at 124 adjacent its outer end.

A drive shaft 126 has its opposed ends rotatably journalled in the bearings 118, 120. An end thereof projects partially into the bore 122 and terminates in neck 121 o-f reduced diameter. The neck 121 is substantially hollow and is open at its outer end. Neck 121 is constructed with iat side walls to form a polygonal shaped socket 128.

A rotary cutter blade shaft 130 is telescoped over the drive shaft 126 and is positioned thereon intermediate its ends. The blade shaft 130 is formed with external threads 132, 134 of opposite hand, and is locked on the drive shaft 126 by set screw 136.

A plurality of rotary cutter blades 138 are slidably mounted over the blade shaft 130 and are secured in side-by-side assembly for rotation therewith. Under some conditions spacer members (not shown) may be interposed between the blades. Lock nuts 140, 142 having internal threads of opposite hand are threaded on the threaded portions 132, 134 to exert pressure on the blades 138 and frictionally jam together the adjacent sides of the cutters to prevent relative rotation therebetween. Spacer members 144, 146 are telescoped over the opposed ends of the drive shaft 126.

The reduced end or neck 121 of the drive shaft 126 is received within the inner end of an elongated bolt 148. As is seen in FIG. 2, bolt 148 has an inner portion externally threaded at 149 in threaded engagement with the internal threads 124 of the bore 122. An integrally formed flange 150 limits the distance the bolt 148 may be threaded into the bore 122 and also serves as a lock washer. The outer end of the bolt 148 terminates in an enlarged, knurled head 151. The bolt 148 is provided with an internal threaded axial bore 152 which commuuicates at its inner end with the inner end of an axial bore 154 of reduced diameter. An externally threaded coupling bolt 156 for a flexible driving cable 158 is threaded into the bore 152. The driving cable 158 terminates in a polygonal shaped driving pin 160 which is inserted within the polygonal shaped socket 128 to eiect a driving connection between the cable and the shaft 126.

The bight portion 90 of the rotary cutter frame 26 has secured thereto, by screws 161, a pair of L-shaped depending guard members 162, 164, the guard members being located on opposite sides of the blades 138 in spaced relation relative thereto.

A handle 166 is secured to the upper side of the bight 90 by means of screws 168.

lIn actual practice, the blades 138 clear the top of block 62 by 0.005 of an inch. In the embodiment of the invention disclosed herein the rotary cutters 138 are preferably 1.250 inches in diameter having a tolerance of 10.000 inch. The blade shaft is 3.75 inches long with an outside diameter of 0.5 inch and accommodates one hundred fifty cutter blades, each of the latter having a hub thickness of 0.020 inch and being keenly sharpened around its circumference. The upper surface of the mounting block 62 is planar and is substantially 3 inches on a side.

In carrying out the method, the rotary cutter frame 26 is moved to one or the other ends of the base 22.

Thereafter, lan elongated backing sheet 200 of plastic material, substantially rectangular in configuration, is placed over the upper end of the block 62. Thereafter a split width skin section 202 is superposed thereon. The sheet 200 and the skin section 202 each have marginal edges overhanging the block 62 which are inserted between the arms 86, 88 of the clamps 80. The springs 76 hold the sheet 200 and skin section 202 under tension to prevent the skin section from wrinkling.

Thereafter the mounting block 24 is disposed on the base 22 with a pair of opposed flanges, 58A and 58C for example, entering the undercut grooves or channels 36, 38. Hold-down bolts 41, 43 are now tightened against the anges 58A and 58C.

The driving means is now energized to effect rotation of the cutter -blades 138 and the operator grasps the knob 112 and turns it to effect rotation of the pinion 106 and consequent movement of the cutter blades toward the sheet 200 and the skin section 202.

The thickness of the sheet 200 is 0.010 inch and that of the skin section substantially 0.012 inch. Thus, aS the rotary cutters 138 are moved across the backing sheet and skin section, the skin will be slit completely through to form a plurality of longitudinally extending substantially rectangular strips of skin disposed in side-by-side relation while the backing sheet is only scored to onehalf its thickness. Since the overhanging marginal edges of the sheet and skin are disposed below the plane of the upper surface of the block 62, these will not be cut or scored.

After this operation, the cutter frame is moved to the other end of the base 22 and the bolts 41, 43 are now backed away from the flanges 58A, 58C, and the mounting block 24 is removed from the base 22.

A cover sheet 204, having a thickness of 0.003 inch, also formed of plastic material, is now placed on top of the split width skin section 202. The longitudinal and lateral dimensions of the cover sheet 204 are substantially the same as those of the split width skin section 202 and the first plastic sheet 200. The second sheet of plastic material 204, after being superposed upon the split width section 202, is folded in overlapped position relative to the block 62. The clamps are then released from the first plastic sheet 200 and the skin section 202 at one side of the block 62 for engagement against the remote sides of the plastic sheets 200, 204. This is repeated until all four sides of the plastic sheets and the skin section have been secured. The block 24 is now rotated 90 about its vertical axis and the flanges 58B, 58D are inserted within the undercut guide channels 36, 38. The hold-down bolts 41, 43 are again tightened to hold the mounting block 24 in position. The operator now grips the knob 112 and rotates the same in the opposite direction to effect reciprocation of the rotary cutter frame 26.

The cutter blades 138 now cut completely through the second sheet of plastic material 204, the split width skin section 202, and merely score the first sheet of plastic material 200 at right angles with respect to the lirst scoring. The depth of this scoring is substantially one-half the thickness of the sheet 200. As a result of these two cutting operations the split width skin section 202 is reduced to 22,500 individual skin segments 206 (see FIG. 7), having dimensions 0.020 x 0.020 x 0.012, which are encased between the two sheets of plastic material (see FIG. 5).

The backing and cover sheets, 200 and 204, respectively, are formed of polyethylene, and to provide the necessary overlap while on the block 62, these sheets, as well as the skin section 202, vary between 3.25 inches and 3.50 inches on a side.

Thereafter the bolts 41, 43 are moved out of engagement with the flanges 58B, 58D to release the block 24 which is then removed from the base 22. The clamps 80 are released from the marginal edges of the two sheets of plastic material 200, 204. The upper sheet 204 of plastic material is now removed from over the segments :for df 'skin assale 'aha the sheer .zoja is bent arutly to form 'a trough 'te permit the transfer 'of the segments, as by fn'nelingl, Vintov a ies'e'rvir` containing. a sterile `-pl'iysiological s'aliiie solution 'to form va suspensiorrtlierein. The blocks yof skin 2.06Q formirig the suspension vmay how be 'wiped across the do'n' are of the ptientfsbskm with a br'usli, 'strile finger 'or `other appropriate instrument, iii accordance with k'rl''wn techniques. i

. `It will be uhdrsto'od that 'the specifieddmeri'si'ns given sbdv may vary 'fo some extent. For example, a gigaset bi' lesser ni'riber 'of 'cutter blades may be used, the clearance between the blades and the block may be increased or decreased, the thickness of the plastic sheets may be different from those specified, etc. However, it has been determined that in most cases, the specific dimensions produce the optimum results.

It will also be understood, that while the described method and apparatus disclosed herein are specifically directed to the field of dermatology, the invention con templates usage in other arts wherein it is desired to reduce a section of a given material, regardless of its configuration but of substantially uniform thickness, into a plurality of independent or individual segments.

Having described and illustrated one embodiment of this invention in detail, it will be understood that the same is offered merely by way of example, and that this invention is to be limited only by the scope of the appended claims.

We claim:

l. A method for preparing a split width skin section for a skin grafting operation comprising the consecutive steps of superposing said section on a smooth backing sheet, cutting entirely through said section and only partially through said backing sheet to obtain a plurality of longitudinally extending substantially rectangular thin strips of skin sections disposed in side-by-side relation, superposing an integral cover sheet on said strips of skin sections, cutting entirely through said cover sheet and through said strips of skin sections and only partially through said backing sheet, both of said cutting steps being made in a linear direction with the latter being made at an angle with respect to the former to provide a plurality of very small individual skin segments.

2. A method for preparing a split width skin section for a skin grafting operation comprising the consecutive steps of superposing said section on a smooth backing sheet, cutting entirely through said section and only partially through said backing sheet to obtain a plurality of longitudinally extending substantially rectangular thin strips of skin sections disposed in side-by-side relation, superposing. a cover sheet on said strips of skin sections, cutting entirely through said cover sheet, said strips of skm sections and only partially through said backing sheet, both of said cutting steps being made in a linear direction with the latter being made at an angle of 90 with respect to the former to provide a plurality of very small individual skin segments having a substantially cubical configuration.

3. A method for preparing a split width skin section for a skin grafting operation comprising the consecutive steps of superposing said section on a smooth backing sheet, placing said section and ysaid backing sheet under tension, cutting entirely through said section and only partially through said backing sheet to obtain a plurality of longitudinally extending substantially rectangular strips of skin sections having a width on the order of 0.02 inch, said sections disposed in side-by-side relation, releasing Said section and said backing sheet from said tension, superposing a cover sheet on said strips of skin sections, cutting entirely through said cover sheet and said strips of said skin sections and only partially through said backing sheet, said last-mentioned cutting comprising a plurality of individual cuts spaced apart by a distance on the order of 0.02 inch, both of said cutting steps being made in a linear direction with the utter seitig at rn 'sagre si ,site

f1 tialiyao; ith respect to the former to provide@ plurality 'of' substantially essieu segmeataetd ich pfwsaid earring "steps, originating and terminating, 'at `points 'spcediiii'vafdly frji the mrgi'nl edges 'f said bever street rfd said -skin section?. a 4 'l 4. A microtome for reducing a split width -skin section into a plurality'of individual segments comprising a substantially Vrectangular base, a substantially rectangular 'split widthjskin vsection mounting block fdisposed on said base, ineans rnounted 'on said base and engaging said bl'ck to secure said block thereon in adjusted relation, an inverted substantially U-shaped cutting blade frame mounted for reciprocation on said base, a plurality of rotary cutter blades mounted for rotation on said frame, said cutter blades clearing said block as said frame is reciprocated, and means connected with said blades to effect rotation thereof, means mounted on said frame and coacting with means mounted on said base to effect reciprocation of said frame relative to said base, and clip means resiliently connected with said mounting block for releasably engaging the marginal edges of said skin section to place said skin section under tension.

5. A device for reducing a split width skin section into a plurality of individual segments, said device comprising a base member, a mounting block secured on said base member, a cutter blade frame mounted for movement across the upper surface of said mounting block, a plurality of cutter blades secured on said cutter blade frame and terminating in a fixed plane closely spaced above said upper surface, a smooth sheet of penetrable solid material disposed in overlying relation on said upper surface and terminating in a surface spaced above said cutter level, said surface being penetrable by said cutting means, holding means for mounting skin sections in overlying relation on said sheet, and a retaining sheet of penetrable material selectively mountable in overlying relation upon said sections independently of said cutter blade frame, said cutter blade frame first being movable horizontally across said upper surface to longitudinally slit said skin section Iand to penetrate said surface of said solid material prior to mounting said retaining sheet upon said skin sections and subsequently being movable horizontally across said upper surface to slit said skin sections and said retaining sheet and penetrating said surface of said solid material at an angle to said longitudinal slits.

6. A microdermatorne for reducing a split width skin section into a plurality of individual skin segments comprising a substantially U-shaped base member, having a bight portion and a pair of laterally spaced side walls, a substantially rectangular skin section mounting block disposed on said bight portion and between said side walls, means extending through said side walls and releasably engaging said block to maintain said block in adjusted relation relative to said base member, a plurality of clamps resiliently connected with said mounting block, said clamps being engageable with the marginal edges of said skin section to hold said section under -tension on said block, an inverted substantially U-shaped Cutter blade frame, said frame including a bight portion and a pair of laterally spaced side walls, means on the upper ends of said first pair of side walls cooperating with means on the lower ends of said last-named pair of side walls to slidably mount said frame on said blade, a plurality of cutter blades supported on said side walls and extending therebetween, said blades clearing said block as said frame is slidably moved relative to said block, and means to effect said sliding movement.

7. A microdermatome as defined in claim 6 wherein said blades are rotary blades, and means to effect rotation of said blades.

8. A microdermatome as defined in claim 7 wherein said means for effecting said sliding movement between said frame and said base member comprise a pinion mounted for rotation on one wall of said last-named pair 7 of side walls and a gear rack xedly mounted on one wall of said rst pair of side walls.

9. A microdermatome as dened in claim 8, and handle means fixedly secured to said bight portion of said frame, and a blade guard xedly secured to said bight portion of said frame on opposite sides of said blades.

Giiord Feb. 4, 1879 Lawrence Mar. 26, 1918 8 Kupter June 7, 1921 Goldberg Aug. 1, 1922 Norris Mar. 1, 1927 Spang Nov. 19, 1929 Kazanji Jan. 5, 1932 Lindstedt et al. Nov. 7, 1939 Marcuse Jan. 26, 1943 Brow et al Sept. 27, 1944 Hyland July 3, 1951 Soell Sept. 4, 1951 Scholl Aug. 30, 1955 

5. A DEVICE FOR REDUCING A SPLIT WIDTH SKIN SECTION INTO A PLURALITY OF INDIVIDUAL SEGMENTS, SAID DEVICE COMPRISING A BASE MEMBER, A MOUNTING BLOCK SECURED ON SAID BASE MEMBER, A CUTTER BLADE FRAME MOUNTED FOR MOVEMENT ACROSS THE UPPER SURFACE OF SAID MOUNTING BLOCK, A PLURALITY OF CUTTER BLADES SECURED ON SAID CUTTER BLADE FRAME AND TERMINATING IN A FIXED PLANE CLOSELY SPACED ABOVE SAID UPPER SURFACE, A SMOOTH SHEET OF PENETRABLE SOLID MATERIAL DISPOSED IN OVERLYING RELATION ON SAID UPPER SURFACE AND TERMINATING IN A SURFACE SPACED ABOVE SAID CUTTER LEVEL, SAID SURFACE BEING PENETRABLE BY SAID CUTTING MEANS, HOLDING MEANS FOR MOUNTING SKIN SECTIONS IN OVERLYING RELATION ON SAID SHEET, AND A RETAINING SHEET OF PENETRABLE MATERIAL SELECTIVELY MOUNTABLE IN OVERLYING RELATION UPON SAID SECTIONS INDEPENDENTLY OF SAID CUTTER BLADE FRAME, SAID CUTTER BLADE FRAME FIRST BEING MOVABLE HORIZONTALLY ACROSS SAID UPPER SURFACE TO LONGITUDINALLY SLIT SAID SKIN SECTION AND TO PENETRATE SAID SURFACE OF SAID SOLID MATERIAL PRIOR TO MOUNTING SAID RETAINING SHEET UPON SAID SKIN SECTIONS AND SUBSEQUENTLY BEING MOVABLE HORIZONTALLY ACROSS SAID UPPER SURFACE TO SLIT SAID SKIN SECTIONS AND SAID RETAINING SHEET AND PENETRATING SAID SURFACE OF SAID SOLID MATERIAL AT AN ANGLE TO SAID LONGITUDINAL SLITS. 